Originally posted by SY Low dynamic impedance is tough to find these days.

What do figure the dynamic impedance is at the current being run? A couple of nights ago I assembled a jig to test AC impedance of LEDs biased by a variable CCS and driven with a sound card. A rough calc suggests the lowest AC impedance LED in the junk box is about 7 ohms at 1000 Hz with 15 ma static DC bias. Are significantly lower to be had? BTW, thanks for the tip on LED biasing, much cheaper than Mills wirewound.

The LEDs I use have an AC impedance of 4.5 ohms. Cheaper than a Mills, and no need for bypassing- gets that whomping electrolytic out of there. But I had to try at least a dozen varieties until I hit one this good.

7 ohms sounds like one of the better "super bright" red.

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“The short explanation is always dull. It generally includes the word ‘just.’ The explanation only becomes beautiful when you immerse yourself in every nuance.”

That's an accurate description of its appearance, small and bright. Unfortunately that's also the only information on them. I buy them in bags-o-LED packaging from the local jobber. Currently using one as cathode load for an Ultrapath 6c45 and it works very, very well.

This is my phono preamp in the first plane. He include tube ECC83. In the next location is phono amp, witch connection from preamp. He include in the first stage 2xE88CC and in the last stage include Russian tube 6H13C.

And this is my next construction. This is a tube amp witch I use when I need quietly play in my home (noice witch made this amp no irritate neighbours . The amp have a clean chanel like a Fender amp. In the first stage I use the ECC83. The next stage include EL84 witch create 4W power. The box this is a wine package.

Two days ago I implementing a new transformers in my OTL. The transformers was made to order. But they isn't dedicate for 6H13C. The transformers was made for 6C33C-B, but this projec to be temporary stop, because i have't much time but soon realized him.

My 6B4G DRD amp, soon to be finished.
Triode wired E81L inputs, LL1664 and LL1621 OPT and plate choke.
The amp is finished and the PSU will be in a couple of days.
Those big chokes at the bottom of the PSU are 25mH 3A double C-core surplus units for the LCLC filament supplys.